OLIGODENDROCYTE/MYELIN GLYCOPROTEIN AND THE P

神经胶质细胞分化的调控及神经胶质轴突的作用机制 相互作用和髓鞘形成是积极研究的领域。我有 以前描述的少突胶质细胞髓鞘糖蛋白 （OMgp）在中枢神经系统（CNS）中的作用。时空 OMgp的表达与中枢神经系统的尾-喙轴相关 髓鞘形成OMgp的结构提供了对 这是中枢神经系统髓鞘形成的基础机制。OMgp包含 富含亮氨酸的重复序列（LRR）结构域，它与 蛋白质间相互作用及其翻译后修饰 包括糖基-磷脂酰肌醇（GPI）连接。有 越来越多的证据表明，GPI锚在激活 酪氨酸激酶途径，在某些情况下， 小囊泡 最近的观察和我们的初步数据表明，OMgp是 存在于周围神经系统（PNS）中，特别是在 髓鞘的结旁区域，并通过髓鞘化施旺氏细胞表达 细胞我们对OMgp在形成中的作用感兴趣， PNS髓鞘的维持。我们推测，OMgp的表达， 有髓鞘的雪旺细胞具有相同的限制性发育， 在CNS中表达为OMgp。凭借其LRR和GPI膜 锚，我们假设OMgp与其他多肽相互作用， 例如轴突或其它细胞上的受体和/或游离配体。我们 我相信这些相互作用将导致酪氨酸激酶激活 和磷酸化的下游途径重要的雪旺细胞 髓鞘形成 当前提案的目的是描述OMgp的 在发育中的许旺细胞中表达，以鉴定分子 与OMgp相互作用，探索由此产生的激活， 酪氨酸激酶途径，并检查转染的 缺乏LRR或GPI锚的OMgp突变形式， 这些途径。我们有四个具体目标： 1.确定周围神经发育过程中OMgp的表达， 2.检测OMgp在雪旺细胞中的体外表达， 3.鉴定与OMgp相互作用的多肽，并表征 OMgp在信号转导中的作用，以及 4.产生突变OMgp构建体，其：i）缺乏LRR结构域，或ii） 以跨膜形式存在并转染这些突变形式的OMgp 转化为永生化的许旺细胞比较多克隆 抗OMgp抗体以诱导髓鞘形成表型和/或 激活天然与突变OMgp中的酪氨酸激酶途径 转染细胞

The control of glial differentiation, and the mechanisms of glia-axon interactions and myelination are areas of active investigation. I have previously characterized the oligodendrocyte-myelin glycoprotein (OMgp) in the central nervous system (CNS). The temporal-spatial expression of OMgp correlates with the caudal-rostral axis of CNS myelination. The structure of OMgp provides insight into the mechanisms which underlie this role in CNS myelination. OMgp contains a leucine-rich repeat (LRR) domain, which has been implicated in protein-protein interactions, and its post-translational modifications include a glycosyl-phosphatidylinositol (GPI) attachment. There is growing evidence that the GPI anchor plays a role in activation of tyrosine kinase pathways, which in some cases localizes within caveolar vesicles. Recent observations and our preliminary data indicate that OMgp is present in the peripheral nervous system (PNS), particularly at the paranodal regions of myelin, and is expressed by myelinating Schwann cells. We are interested in OMgp's role in the formation and maintenance of PNS myelin. We speculate that OMgp's expression by myelinating Schwann cells has the same restricted developmental expression as OMgp in the CNS. By virtue of its LRRs and GPI membrane anchor, we hypothesize that OMgp interacts with other polypeptides, such as receptors on axons or other cells and/or free ligands. We believe these interactions will result in tyrosine kinase activation and phosphorylation of downstream pathways important in Schwann cell myelination. The purpose of the current proposal is to characterize OMgp's expression within developing Schwann cells, to identify the molecules which interact with OMgp, to explore the resultant activation of tyrosine kinase pathways, and to examine the effects of transfected mutant forms of OMgp which lack either the LRRs or the GPI anchor on these pathways. We have four specific aims: 1. Determine OMgp expression during peripheral nerve development, 2. Examine in vitro expression of OMgp in Schwann cells, 3. Identify polypeptides which interact with OMgp and characterize the role of OMgp in signal transduction, and 4. Create mutant OMgp constructs which: i) lack the LRR domain, or ii) exist as a transmembrane form and transfect these mutant forms of OMgp into immortalized Schwann cells. Compare the ability of polyclonal anti-OMgp antibodies to induce a myelinating phenotype and/or to activate tyrosine kinase pathways in native vs. mutant OMgp transfected cells.